Stay bolt for boilers



Jan. 12 ,1926. 1,568,981

F. K. LANDGRAF STAY BOLT FOR BOILERS Filed Sept. 14, 1921 Patented Jan. 12, 1926.

PATENT OFFICE.

FREDERICK K. LANDGRAF, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO FLAN- NERY BOLT COMPANY, OF PITTSBURGH, PENNSYLVANIA.

STAY BOLT Application filed September To (r'l Z 40/1012; 21/; may concern:

Be it known that I, l nnonnrcn K. Lannonir, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Sta-y Bolts for Boilers; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improvements in staybolts for boilers and more particularly to those of the fle3ible type in which the bolt is provided with a rounded head to be movably mounted in a bearing member carried by the outer boiler sheet.

Gne object of my present invention is to so construct a staybolt of the flexible type as to economize in material forming the body or shank aortion of the bolt; so that its tire-box end shall be available for adapting the same to pass through threaded holes of difierent sizes in the fire-box sheet of the boiler construction, and so that ample clearance between the bolt and the bearing devices shall be provided, to permit free movement of the bolt during expansion and contraction of the boiler sheets, even though two sheets connected by the bolt be disd at an angle, one to the other. i. ith this and other objects in view, the invention consists in certain novel features as hereinafter set forth and pointed out in the claim.

The accompanying drawing represents an embodiment of my invention.

My improved flexible staybolt comprises a forged or rolled out body or shank l and a rounded head 2 upset or forged on one end of said body or shank said body or shank having a contracted intermediation portion 3, from one end of which, the body or shank tapers to form a neck as at 5 which increases gradually in diameter to the rounded head :2, and from the other end of FOR BOILERS.

14, 1921. Serial no. 500,644.

the contracted intermediate portion 3, the body or shank increases gradually in diameter (forming a tapering portion 6) to the inner end portion 7 of the bolt,said inner end portion being threaded to pass through a threaded hole in the fire-box sheet.

in constructing my improved bolt a bar or blank having a diameter of one inch and a quarter, more or less, is heated and the rounded head 2 is formed on one end thereof by forging in suitable dies. The thick portion 5 adjacent to the head is then tapered down by forging or rolling to the desired diameter forming the intermediate portion 3 of reduced diameter and the tapering portion 6 between the reduced portion 8 and the threaded inner end portion 7. which latter may be of the same diameter as that of the original bar or blank,say one inch and a quarter. It is evident that the blank may be greater or less in diameter than above stated and that by making the inner end portion 7 greater in diameter than that of the intermediate portion 3, said end portion 7 may be reduced more or less in diameter by rolling or forging so that its threaded por ion may be adapted to holes of different sizes in the fire-box sheet.

Having fully described my invention what I. claim as new and desire to secure by Letters-Patent, is:

A flexible staybolt having a rounded head. at one end and having its other end portion threaded, said bolt having a contracted cy lindrical intermediate portion and a tapering neck portion between one end of said contracted cylindrical intermediate portion and the bolt head, the threaded portion having greater diameter than the intermediate portion, and said bolt also having a tapering port-ion between said contracted cylindrical portion and the threaded portion of the bolt.

In testimony whereof, I have signed this specification.

FREDERICK K. LANDGRAF. 

